One of the hardest things for people to accept about the leading cause of death for infants and up to 2,500 children before their first birthday each year in the U.S. is the fact that there is no known cause, hence the name sudden infant death syndrome.
But scientists supported by the National Institutes of Health believe they might have identified a clue.
The study found that more than 40 percent of infants with SIDS as a cause of death had a brain abnormality that affected the area involved with breathing, heart rate and body temperature. While 40 percent is by no means all infants who were said to have died of SIDS in the study, the researchers said the brain abnormality was seen more often in SIDS babies than those who died of known causes. The scientists don't know for sure that the abnormality played a role in the cause of death though.
“The new finding adds to a growing body of evidence that brain abnormalities may underlie many cases of sudden infant death syndrome,” said Dr. Marian Willinger with the Eunice Kennedy Shriver National Institute of Child Health and Human Development. “The hope is that research efforts in this area eventually will provide the means to identify vulnerable infants so that we’ll be able to reduce their risk for SIDS.”
The abnormality was seen in the dentate gyrus, a structure in the hippocampus. Some babies who died of SIDS had a double layer of nerve cells in the dentate gyrus, rather than one layer.
“The pattern of abnormal changes in the dentate gyrus suggests to us there was a problem in its development at some point in late fetal life or in the months right after birth,” Dr. Hannah Kinney, lead researcher from Boston Children’s Hospital and Harvard Medical School, said in a statement. “We didn’t see any signs of injury to the brain by low oxygen levels in the tissue we examined, such as scarring and loss of nerve cells.”
Kinney added that more research is needed to determine what triggered a possible instability in this region of the brain as well as ways to detect the abnormality in a live infant. She also didn't rule out the possibility of an unwitnessed seizure leading to SIDS as well.
SIDS, Kinney said, is likely the result of many different causes, not just one factor.
“The story of SIDS research is far from complete,” Kinney said. “Until it is, the best ways to reduce the risk for SIDS is by following the recommendations for safe sleep and other infant care practices of the Safe to Sleep campaign.”
The study was published in the online journal Acta Neuropathologica.
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